Expandable scaffolding with a rigid, central beam

ABSTRACT

An intervertebral scaffolding system is provided having a rigid central beam and a laterovertically-expanding frame operable for a reversible collapse from an expanded state into a collapsed state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/169,049, filed Oct. 24, 2018, which is a continuation of U.S. patentapplication Ser. No. 15/091,535, filed Apr. 5, 2016, now U.S. Pat. No.10,149,773, which is a continuation of U.S. patent application Ser. No.14/157,504, filed Jan. 16, 2014, now U.S. Pat. No. 9,333,092, which is acontinuation of U.S. patent application Ser. No. 13/815,787, filed Mar.15, 2013, now U.S. Pat. No. 8,663,332, which claims the benefit of U.S.Provisional Application No. 61/737,054, filed Dec. 13, 2012, each ofwhich is hereby incorporated herein by reference in it's entirety.

BACKGROUND Field of the Invention

The teachings herein are directed to a system for distributing bonegraft material in an intervertebral disc space.

Description of the Related Art

Bone grafts are used in spinal fusion, for example, which is a techniqueused to stabilize the spinal bones, or vertebrae, and a goal is tocreate a solid bridge of bone between two or more vertebrae. The fusionprocess includes “arthrodesis”, which can be thought of as the mendingor welding together of two bones in a spinal joint space, much like abroken arm or leg healing in a cast. Spinal fusion may be recommendedfor a variety of conditions that might include, for example, aspondylolisthesis, a degenerative disc disease, a recurrent discherniation, or perhaps to correct a prior surgery.

Bone graft material is introduced for fusion and a fusion cage can beinserted to help support the disc space during the fusion process. Infact, fusion cages are frequently used in such procedures to support andstabilize the disc space until bone graft unites the bone of theopposing vertebral endplates in the disc space. A transforaminal lumbarinterbody fusion (TLIF), for example, involves placement of posteriorinstrumentation (screws and rods) into the spine, and the fusion cageloaded with bone graft can be inserted into the disc space. Bone graftmaterial can be pre-packed in the disc space or packed after the cage isinserted. TLIF can be used to facilitate stability in the front and backparts of the lumbar spine promoting interbody fusion in the anteriorportion of the spine. Fusion in this region can be beneficial, becausethe anterior interbody space includes an increased area for bone toheal, as well as to handle increased forces that are distributed throughthis area.

Unfortunately, therein lies a problem solved by the teachings providedherein. Currently available systems can be problematic in that themethods of introducing the fusion cage and bone graft material leavespockets in regions of the intervertebral space that are not filled withbone graft material, regions in which fusion is desired for structuralsupport. These pockets can create a premature failure of the fusedintervertebral space due to forces that are distributed through theregions containing the pockets, for example, when the patient stands andwalks.

Traditional fusion cages, such as the Medtronic CAPSTONE cage, aredesigned to be oversized relative to the disc space to distract the discspace as the entire cage is inserted. However, this makes it difficultto insert and position properly. In response to the problem, the art hasdeveloped a number of new fusion cages, such as the Globus CALIBER cagewhich can be inserted at a low height and expanded vertically todistract the disc space. Unfortunately, these types of devices have thetypical graft distribution problem discussed above, in that they do notprovide a path for bone graft to be inserted and fill in the spacesurrounding the cage or within the cage. They have other problems aswell, including that the annulotomy must be large to accommodate a largeenough cage for stability, and this large opening necessitates moretrauma to the patient. Moreover, they can also create the additionalproblem of “backout”, in that they cannot expand laterally beyond theannulotomy to increase the lateral footprint of the cage relative tolateral dimension of the annulotomy. Since it takes several months forthe fusion to occur to completion in a patient, the devices have plentyof time to work their way out of the space through the large annulotomy.

Accordingly, and for at least the above reasons, those of skill in theart will appreciate bone graft distribution systems that facilitate animproved distribution of graft material throughout the intervertebralspace. Such systems are provided herein, the systems configured to (i)effectively distribute bone graft material both from the system, andaround the system, to improve the strength and integrity of a fusion;(ii) reduce or eliminate the problem of failures resulting from a poorbone graft distribution; (iii) have a small maximum dimension in acollapsed state for a low-profile insertion into the annulus in aminimally-invasive manner, whether using only a unilateral approach or abilateral approach; (iv) laterally expand within the intervertebralspace to avoid backout of the system through the annulotomy; (v)vertically expand for distraction of the intervertebral space; and, (vi)provide an expansion in the intervertebral space without contracting thesystem in length to maintain a large footprint and an anterior positionadjacent to the inner, anterior annulus wall, distributing load over alarger area, anteriorly, against the endplates.

SUMMARY

The teachings herein are generally directed to a system for distributingbone graft material in an intervertebral disc space. The graftdistribution systems can have, for example, a central beam having aproximal portion having an end, a grafting portion having a top and abottom, a distal portion having a end, a central beam axis, a graftdistribution channel having an entry port at the end of the proximalportion, a top exit port at the top of the grafting portion, and abottom exit port at the bottom of the grafting portion. These systemscan also include a laterovertically-expanding frame having a lumen, afirst top beam, a second top beam, a first bottom beam, and a secondbottom beam, each having a proximal portion and a distal portion, andeach operably connected to each other at their respective proximalportions and distal portions with connector elements to form thelaterovertically-expanding frame that is operable for a reversiblecollapse from an expanded state into a collapsed state. The expandedstate, for example, can be configured to have an open graft distributionwindow that at least substantially closes upon the reversible collapse.In these embodiments, the laterovertically-expanding frame is adaptedfor receiving an insertion of the central beam to form the graftdistribution system.

In some embodiments, the graft distribution systems can have a centralbeam with a central beam axis, a graft distribution channel with anentry port in fluid communication with a top exit port, and a bottomexit port. The central beam can also have a proximal portion having andend with the entry port, a grafting portion having the top exit port andthe bottom exit port, and a distal portion. The central beam can also besized to have a transverse cross-section having a maximum dimensionranging from 5 mm to 15 mm for placing the central beam into anintervertebral space through an annular opening having a maximum lateraldimension ranging from 5 mm to 15 mm, the intervertebral space having atop vertebral plate and a bottom vertebral plate. The central beam canalso have a top surface with a first top-lateral surface and a secondtop-lateral surface, a bottom surface with a first bottom-lateralsurface and a second bottom-lateral surface, a first side surface with afirst top-side surface and a first bottom-side surface, and a secondside surface with a second top-side surface and a second bottom-sidesurface.

The graft distribution system can also comprise alaterovertically-expanding frame configured for operably contacting thecentral beam to create a graft distribution system in vivo, the framehaving a collapsed state with a transverse cross section having amaximum dimension ranging from 5 mm to 15 mm for placing the frame inthe intervertebral space through the annular opening for expansion.Likewise, the frame can also have an expanded state with a transversecross section having a maximum dimension ranging from 6.5 mm to 18 mmfor retaining the frame in the intervertebral space, the expanded stateoperably contacting with the central beam in the intervertebral space.The frame can be defined as including a proximal portion having an end,a grafting portion, a distal portion having an end, and a central frameaxis of the expanded state.

The frame can be configured to have a first top beam including aproximal portion having an end, a grafting portion, and a distal portionhaving an end, the first top beam configured for contacting the firsttop-lateral surface of the central beam and the first top-side surfaceof the central beam in the expanded state, the central axis of the firsttop beam at least substantially on (i) a top plane containing thecentral axis of the first top beam and the central axis of a second topbeam and (ii) a first side plane containing the central axis of thefirst top beam and the central axis of a first bottom beam. Likewise,the frame can be configured to have a second top beam including aproximal portion having an end, a grafting portion having an end, and adistal portion (not shown) having an end, the second top beam configuredfor contacting the second top-lateral surface of the central beam andthe second top-side surface of the central beam in the expanded state,the central axis of the second top beam at least substantially on (i)the top plane and (ii) a second side plane containing the central axisof the second top beam and the central axis of a second bottom beam.Likewise, the frame can be configured to have a first bottom beamincluding a proximal portion having an end, a grafting portion, and adistal portion having an end, the first bottom beam configured forcontacting the first bottom-lateral surface of the central beam and thefirst bottom-side surface of the central beam in the expanded state, thecentral axis of the first bottom beam at least substantially on (i) abottom plane containing the central axis of the first bottom beam andthe central axis of a second top beam and (ii) the first side plane.Likewise, the frame can be configured to have a second bottom beamincluding a proximal portion having an end, a grafting portion having anend, and a distal region having an end, the second bottom beamconfigured for contacting the second bottom-lateral surface of thecentral beam and the second bottom-side surface of the central beam inthe expanded state, the central axis of the second bottom beam being atleast substantially on (i) the bottom plane and (ii) a second side planecontaining the central axis of the second bottom beam and the second topbeam.

The beams of the laterovertically-expanding frame can be operablyconnected through connector elements. As such, the frame can include aplurality of proximal top connector elements configured to expandablyconnect the proximal portion of the first top beam to the proximalportion of the second top beam, the expanding consisting of a flexing atleast substantially on a top plane containing the central axis of thefirst top beam and the central axis of the second top beam. Likewise theframe can be configured to have a plurality of distal top connectorelements configured to expandably connect the distal portion of thefirst top beam to the distal portion of the second top beam, theexpanding consisting of a flexing at least substantially on the topplane.

Likewise, the frame can be configured to have a plurality of proximalbottom connector elements configured to expandably connect the proximalportion of the first bottom beam to the proximal portion of the secondbottom beam, the expanding consisting of a flexing at leastsubstantially on a bottom plane containing the central axis of the firstbottom beam and the central axis of the second bottom beam. Likewise,the frame can be configured to have a plurality of distal bottomconnector elements configured to expandably connect the distal portionof the first bottom beam to the distal portion of the second bottombeam, the expanding consisting of a flexing at least substantially onthe bottom plane.

Likewise, the frame can be configured to have a plurality of proximalfirst side connector elements configured to expandably connect theproximal portion of the first top beam to the proximal portion of thefirst bottom beam, the expanding consisting of a flexing at leastsubstantially on a first side plane containing the central axis of thefirst top beam and the central axis of the first bottom beam; aplurality of distal first side connector elements (not shown) configuredto expandably connect the distal portion of the first top beam to thedistal portion of the first bottom beam, the expanding consisting of aflexing at least substantially on the first side plane. Likewise theframe can be configured to have a plurality of proximal second sideconnector elements configured to expandably connect the proximal portionof the second top beam to the proximal portion of the second bottombeam, the expanding consisting of a flexing at least substantially on asecond side plane containing the central axis of the second top beam andthe central axis of the second bottom beam; a plurality of distal secondside connector elements configured to expandably connect the distalportion of the second top beam to the distal portion of the secondbottom beam, the expanding consisting of a flexing at leastsubstantially on the second side plane;

The frame can be configured for slidably engaging with the central beamin vivo following placement of the central beam in the intervertebralspace through the annular opening, the slidably engaging includingtranslating the central beam into the frame from the proximal end of theframe toward the distal end of the frame in vivo; the translatingincluding keeping the central beam axis at least substantiallycoincident with the central frame axis during the translating to createthe graft distribution system in vivo through the annular opening. Thegraft distribution system can also be configured to form a topgraft-slab depth between the top surface of the central beam and the topvertebral endplate; and, a bottom graft-slab depth between the bottomsurface of the central beam and the bottom vertebral endplate in vivo.And, in some embodiments, the transverse cross-section of the graftdistribution system in vivo is greater than the maximum lateraldimension of the annular opening to avoid backout.

The distal end of the frame can be configured to have a lateroverticallyoperable connection with a guide plate connectable to the guidewire thatrestricts the first top beam, the first bottom beam, the second topbeam, and the second bottom beam to laterovertical movement relative tothe guide plate and the guidewire when converting the frame from thecollapsed state to the expanded state in vivo. And, in some embodiments,the laterovertically-expandable frame has a lumen, and the guide platehas a luminal side with connector for reversibly receiving a guide wirefor inserting the laterovertically-expandable frame into theintervertebral space.

One of skill will appreciate that the central beam can have anyconfiguration that would be operable with the teachings provided herein.In some embodiments, criteria for a suitable central beam may include acombination of a material and configuration that provides a suitablestiffness. In some embodiments, the central beam can comprise an I-beam.

One of skill will further appreciate that the central beam can have anyone or any combination of graft port configurations that would beoperable with the teachings provided herein. In some embodiments,criteria for a suitable graft port configuration may include acombination of port size, number of ports, and placement of ports. Insome embodiments, the central beam can comprise a side graft port.

One of skill will further appreciate that the connector elements canvary in design but should meet the constraints as taught herein. In someembodiments, for example each of the connector elements can have across-sectional aspect ratio of longitudinal thickness to transversethickness ranging from 1:2 to 1:8.

In some embodiments, each of the plurality of proximal connectorelements are proximal struts configured in an at least substantiallyparallel alignment in the expanded state; and, each of the distalconnector elements are distal struts configured in an at leastsubstantially parallel alignment in the expanded state. Likewise, insome embodiments, each of the plurality of proximal connector elementsare proximal struts configured in an at least substantially parallelalignment in the collapsed state; and, each of the distal connectorelements are distal struts configured in an at least substantiallyparallel alignment in the collapsed state. Moreover, in someembodiments, each of the plurality of proximal connector elements areproximal struts configured in an at least substantially parallelalignment in the expanded state and the collapsed state; and, each ofthe distal connector elements are distal struts configured in an atleast substantially parallel alignment in the expanded state and thecollapsed state.

In some embodiments, each plurality of proximal top connector elementsand proximal bottom connector elements are proximal struts configured inan at least substantially parallel alignment in the expanded state andthe collapsed state; and, each plurality of distal top connectorelements and distal bottom connector elements are distal strutsconfigured in an at least substantially parallel alignment in theexpanded state and the collapsed state. In some embodiments, theproximal top struts are configured monolithically integral to the firsttop beam and the second top beam and adapted to flex toward the distaltop struts during collapse; and, the distal top struts are configuredmonolithically integral to the first top beam and the second top beamand adapted to flex toward the proximal top struts during collapse.Likewise, in some embodiments, the proximal bottom struts are configuredmonolithically integral to the first bottom beam and the second bottombeam and adapted to flex toward the distal bottom struts duringcollapse; and, the distal bottom struts are configured monolithicallyintegral to the first bottom beam and the second bottom beam and adaptedto flex toward the proximal bottom struts during collapse. And, in theseembodiments, the top and bottom of the laterovertically-expanding frameare each configured to open a graft distribution window upon expansionto facilitate graft distribution within the intervertebral space.

In some embodiments, the central beam further comprises a first sidegraft port and a second side graft port. In these embodiments, eachplurality of proximal connector elements can be configured as proximalstruts in an at least substantially parallel alignment in the expandedstate and the collapsed state; and, each plurality distal connectorelements are distal struts can be configured in an at leastsubstantially parallel alignment in the expanded state and the collapsedstate. As such, the proximal top struts can be configured monolithicallyintegral to the first top beam and the second top beam and adapted toflex toward the distal top struts during collapse; and, the distal topstruts can be configured monolithically integral to the first top beamand the second top beam and adapted to flex toward the proximal topstruts during collapse. Likewise, the proximal bottom struts can beconfigured monolithically integral to the first bottom beam and thesecond bottom beam and adapted to flex toward the distal bottom strutsduring collapse; and, the distal bottom struts can be configuredmonolithically integral to the first bottom beam and the second bottombeam and adapted to flex toward the proximal bottom struts duringcollapse. Likewise, the proximal first side struts can be configuredmonolithically integral to the first top beam and the first bottom beamand adapted to flex toward the distal first side struts during collapse;and, the distal first side struts can be configured monolithicallyintegral to the first top beam and the first bottom beam and adapted toflex toward the proximal first side struts during collapse. Likewise,the proximal second side struts can be configured monolithicallyintegral to the second top beam and the second bottom beam and adaptedto flex toward the distal second side struts during collapse; and, thedistal second side struts can be configured monolithically integral tothe second top beam and the second bottom beam and adapted to flextoward the proximal second side struts during collapse. As such, in someembodiments, the top, bottom, first side, and second side of thelaterovertically-expanding frame can be configured to form amonolithically integral frame, each adapted to open a graft distributionwindow 188 upon expansion to facilitate graft distribution within theintervertebral space.

The teachings are also directed to a method of fusing an intervertebralspace using any of the graft distribution systems taught herein. Themethods can include creating a single point of entry into anintervertebral disc, the intervertebral disc having a nucleus pulposussurrounded by an annulus fibrosis, and the single point of entry havingthe maximum lateral dimension created through the annulus fibrosis. Themethods can also include removing the nucleus pulposus from within theintervertebral disc through the single point of entry, leaving theintervertebral space for expansion of the graft distribution systemwithin the annulus fibrosis, the intervertebral space having the topvertebral plate and the bottom vertebral plate. The methods can alsoinclude inserting the laterovertically expanding frame in the collapsedstate through the single point of entry into the intervertebral space;and, inserting the central beam into the frame to form the graftdistribution system. Moreover, the methods can also include adding agrafting material to the intervertebral space through the entry port.

The bone graft distribution systems provided herein include bone graftwindows defined by the connector elements, the bone graft windowsopening upon expansion of the laterovertically expanding frame. In someembodiments, the method further comprises opening a bone graft window,wherein the connector elements include v-shaped struts that (i) stackeither proximally or distally in a closed-complementary configuration inthe collapsed state to minimize void space for a low profile entry ofthe system both vertically and laterally into the intervertebral space,and (ii) deflect upon expansion to open the bone graft window.

The bone graft distribution systems provided herein also allow forindependent expansion laterally and vertically by expanding in steps. Insome embodiments, the expanding includes selecting an amount of lateralexpansion independent of an amount of vertical expansion. And, in someembodiments, the lateral expansion exceeds the width of the annularopening that is the single point of entry into the intervertebral space.For example, the lateral dimension of the single point of entry canrange from about 5 mm to about 15 mm in some embodiments. As such, insome embodiments, the expanding includes expanding the lateroverticallyexpanding frame laterally to a width that exceeds the width of thesingle point of entry; and, inserting the central beam to expand thelaterovertically expanding frame vertically to create the graftdistribution system.

The bone graft distribution systems provided herein also have means forretaining the central beam in the laterovertically expanding frame. Insome embodiments, the inserting of the central beam into thelaterovertically expanding frame includes engaging a ratchet mechanismcomprising a protuberance on the central beam that engages with thelaterovertically-expanding frame to prevent the central beam frombacking out of the laterovertically-expanding frame after the expanding.

The bone graft distribution systems provided here can be in the form ofa kit. The kits can include, for example, a graft distribution systemtaught herein, a cannula for inserting the graft distribution systeminto the intervertebral space, a guidewire adapted for guiding thecentral beam into the laterovertically expanding frame, and an expansionhandle for inserting the central beam into the lateroverticallyexpanding frame to form the graft distribution system.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1I illustrate components of the graft distribution system,according to some embodiments.

FIGS. 2A-2F illustrate a method of using a bidirectionally-expandablecage, according to some embodiments.

FIGS. 3A-3D illustrate a bidirectionally-expandable cage for fusing anintervertebral disc space, according to some embodiments.

FIGS. 4A and 4B illustrate collapsed and expanded views of abidirectionally-expandable cage having a bone graft window on each wallfor fusing an intervertebral disc space, according to some embodiments.

FIGS. 5A-5D illustrate system for fusing an intervertebral disc space,according to some embodiments.

FIG. 6 is a diagram of a method of using a bidirectionally-expandablecage, according to some embodiments.

FIGS. 7A-7F illustrate some additional features of graft distributionsystems, according to some embodiments.

FIGS. 8A-8D illustrate components of a graft distribution kit, accordingto some embodiments.

FIGS. 9A-9C illustrate the expansion of a laterovertically-expandableframe in an intervertebral space, according to some embodiments.

FIGS. 10A-10C illustrate profiles of an expanded graft distributionsystem to highlight the exit ports and bone graft windows, according tosome embodiments.

FIGS. 11A and 11B compare an illustration of the graft distribution inplace to a test placement in a cadaver to show relative size, accordingto some embodiments.

FIGS. 12A-12C show x-rays of a placement in a cadaver, according to someembodiments.

FIGS. 13A-13D show orientations of the first top beam relative to thesecond top beam, first bottom beam relative to the second bottom beam,first top beam relative to the first bottom beam, and the second topbeam relative to the second bottom beam, according to some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

The teachings herein are generally directed to a system for distributingbone graft material in an intervertebral disc space. The graftdistribution systems can have, for example, a central beam having aproximal portion having an end, a grafting portion having a top and abottom, a distal portion having a end, a central beam axis, a graftdistribution channel having an entry port at the end of the proximalportion, a top exit port at the top of the grafting portion, and abottom exit port at the bottom of the grafting portion. These systemscan also include a laterovertically-expanding frame having a lumen, afirst top beam, a second top beam, a first bottom beam, and a secondbottom beam, each having a proximal portion and a distal portion, andeach operably connected to each other at their respective proximalportions and distal portions with connector elements to form thelaterovertically-expanding frame that is operable for a reversiblecollapse from an expanded state into a collapsed state. The expandedstate, for example, can be configured to have an open graft distributionwindow that at least substantially closes upon the reversible collapse.In these embodiments, the laterovertically-expanding frame is adaptedfor receiving an insertion of the central beam to form the graftdistribution system.

In some embodiments, the graft distribution systems can also include alaterovertically-expanding frame having a first top beam, a second topbeam, a first bottom beam, and a second bottom beam; wherein, the beamsare in an at least substantially parallel arrangement with each other,each having a proximal portion, a grafting portion, and a distalportion, and each operably connected to each other at their respectiveproximal portions and distal portions to form thelaterovertically-expanding frame in a square, cylindrical shape that isoperable for a reversible collapse from an expanded state into acollapsed state. The expanded state, for example, can be configured tohave an open graft distribution window that at least substantiallycloses upon the reversible collapse. In these embodiments, thelaterovertically-expanding frame is adapted for receiving an insertionof the central beam to form the graft distribution system.

The term “subject” and “patient” can be used interchangeably in someembodiments and refer to an animal such as a mammal including, but notlimited to, non-primates such as, for example, a cow, pig, horse, cat,dog; and primates such as, for example, a monkey or a human. As such,the terms “subject” and “patient” can also be applied to non-humanbiologic applications including, but not limited to, veterinary,companion animals, commercial livestock, and the like. Moreover, termsof degree are used herein to provide relative relationships between theposition and/or movements of components of the systems taught herein.For example, the phrase “at least substantially parallel” is used torefer to a position of one component relative to another. An axis thatis at least substantially parallel to another axis refers to anorientation that is intended, for all practical purposes to be parallel,but it is understood that this is just a convenient reference and thatthere can be variations due to stresses internal to the system andimperfections in the devices and systems. Likewise, the phrase “at leastsubstantially on a . . . plane” refers to an orientation or movementthat is intended, for all practical purposes to be on or near the planeas a convenient measure of the orientation or movement, but it isunderstood that this is just a convenient reference and that there canbe variations due to stresses internal to the system and imperfectionsin the devices and systems. Likewise, the phrase “at least substantiallycoincident” refers to an orientation or movement that is intended, forall practical purposes to be on or near, for example, an axis or a planeas a convenient measure of the orientation or movement, but it isunderstood that this is just a convenient reference and that there canbe variations due to stresses internal to the system and imperfectionsin the devices and systems.

FIGS. 1A-1I illustrate components of the graft distribution system,according to some embodiments. As shown in FIG. 1A, the graftdistribution systems 100 can have a central beam 101 with a central beamaxis 105, a graft distribution channel with an entry port 135 in fluidcommunication with a top exit port 140, and a bottom exit port 141. Thecentral beam 101 can also have a proximal portion 111 having and endwith the entry port 135, a grafting portion 112 having the top exit port140 and the bottom exit port 141, and a distal portion (not shown). Thecentral beam 101 can also be sized to have a transverse cross-section110 having a maximum dimension ranging from 5 mm to 15 mm for placingthe central beam 101 into an intervertebral space through an annularopening having a maximum lateral dimension ranging from 5 mm to 15 mm,the intervertebral space having a top vertebral plate and a bottomvertebral plate. The central beam 101 can also have a top surface 115with a first top-lateral surface 117 and a second top-lateral surface119, a bottom surface 120 with a first bottom-lateral surface 122 and asecond bottom-lateral surface 124, a first side surface 125 with a firsttop-side surface 127 and a first bottom-side surface 129, and a secondside surface 130 with a second top-side surface 132 and a secondbottom-side surface 134.

In some embodiments, the central beam can have transversecross-sectional lateral dimension ranging from about 5 mm to about 15mm. In some embodiments, the vertical dimension of the central beam canrange from about 4 mm to about 12 mm, about 5 mm to about 11 mm, about 6mm to about 10 mm, and about 7 mm to about 9 mm, about 6 mm to about 8mm, about 6 mm, or any range or amount therein in increments of 1 mm. Insome embodiments, the lateral dimension of the central beam can rangefrom about 5 mm to about 15 mm, about 6 mm to about 14 mm, about 7 mm toabout 13 mm, about 8 mm to about 12 mm, about 10 mm, or any range oramount therein in increments of 1 mm. In some embodiments, transversecross-section of the central beam has an area with an effective diameterranging from about 2 mm to about 20 mm, from about 3 mm to about 18 mm,from about 4 mm to about 16 mm, from about 5 mm to about 14 mm, fromabout 6 mm to about 12 mm, from about 7 mm to about 10 mm, or any rangetherein. In some embodiments, the low profile has an area with adiameter of 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm,or any range therein, including any increment of 1 mm in any suchdiameter or range therein. In some embodiments, the width (mm)×height(mm) of the central beam can be 9.0×5.0, 9.0×6.0, 9.0×7.0, 9.0×8.0,9.0×9.0, and 9.0×10.0, or any deviation in dimension therein inincrements of +/−0.1 mm. And, in some embodiments, the central beam canhave a transverse cross-sectional lateral or vertical dimension thatranges from 6.5 mm to 14.0 mm.

As shown in FIGS. 1B and 10, the graft distribution system 100 can alsocomprise a laterovertically-expanding frame 149 configured for operablycontacting the central beam 101 to create a graft distribution system100 in vivo, the frame 149 having a collapsed state 149 c with atransverse cross section 149 ct having a maximum dimension ranging from5 mm to 15 mm for placing the frame 149 in the intervertebral spacethrough the annular opening for expansion. Likewise, the frame 149 canalso have an expanded state 149 e with a transverse cross section 149 ethaving a maximum dimension ranging from 6.5 mm to 18 mm for retainingthe frame 149 in the intervertebral space, the expanded state operablycontacting with the central beam 101 in the intervertebral space. Theframe 149 can be defined as including a proximal portion 111 having anend, a grafting portion 112, a distal portion (not shown) having an end,and a central frame axis 113 of the expanded state 149 e.

In some embodiments, the frame can have transverse cross-sectionallateral dimension in the collapsed state ranging from about 5 mm toabout 15 mm. In some embodiments, the vertical dimension of the frame inthe collapsed state can range from about 4 mm to about 12 mm, about 5 mmto about 11 mm, about 6 mm to about 10 mm, and about 7 mm to about 9 mm,about 6 mm to about 8 mm, about 6 mm, or any range or amount therein inincrements of 1 mm. In some embodiments, the lateral dimension of theframe in the collapsed state can range from about 5 mm to about 15 mm,about 6 mm to about 14 mm, about 7 mm to about 13 mm, about 8 mm toabout 12 mm, about 10 mm, or any range or amount therein in incrementsof 1 mm. In some embodiments, transverse cross-section of the frame inthe collapsed state has an area with an effective diameter ranging fromabout 2 mm to about 20 mm, from about 3 mm to about 18 mm, from about 4mm to about 16 mm, from about 5 mm to about 14 mm, from about 6 mm toabout 12 mm, from about 7 mm to about 10 mm, or any range therein. Insome embodiments, the low profile has an area with a diameter of 2 mm, 4mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or any range therein,including any increment of 1 mm in any such diameter or range therein.In some embodiments, the width (mm)×height (mm) of the frame in thecollapsed state can be 9.0×5.0, 9.0×6.0, 9.0×7.0, 9.0×8.0, 9.0×9.0, and9.0×10.0, or any deviation in dimension therein in increments of +/−0.1mm. In some embodiments, the frame can have a transverse cross-sectionaldimension, lateral or vertical in the expanded state ranging from 4.0 mmto 18 mm, from 5.0 mm to 19.0 mm, from 6.0 mm to 17.5 mm, from 7.0 mm to17.0 mm, from 8.0 mm to 16.5 mm, from 9.0 mm to 16.0 mm, from 9.0 mm to15.5 mm, from 6.5 mm to 15.5 mm, or any range or amount therein inincrements of +/−0.1 mm.

The term “collapsed state” can be used to refer to a configuration ofthe frame in which the transverse cross-sectional area, or profile, isat least substantially at it's minimum, and the term “expanded state”can be used to refer to a configuration of the frame that is expanded atleast substantially beyond the collapsed state. In this context, a frameis expanded at least “substantially” beyond the collapsed state when abone graft window of the frame has opened from the closed configurationby at least a 20% increase area of the bone graft window from thecollapsed state. In some embodiments, the frame is expanded at least“substantially” beyond the collapsed state when a bone graft window ofthe frame has opened by at least a 15%, 20%, 25%, 30%, 35%, 40%, 45%,50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, 250%, 300%, or more whencompared to the bone graft window from the collapsed state. In someembodiments, the frame is expanded at least “substantially” beyond thecollapsed state when a bone graft window of the frame has opened by atleast 2×, 3×, 5×, 10×, 15×, 20×, or more when compared to the bone graftwindow from the collapsed state.

In some embodiments, the laterovertically expandable frames are createdin an expanded state. And the expanded state can include a state that isat least 30%, at least 40%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 95% of the full expansion. The term“full expansion” can be used to refer to an extent of expansion uponwhich a connector element begins to fatigue, fail, or crack; or, in someembodiments, strain beyond 10%, 20%, or 30%.

The frame 149 can be configured to have a first top beam 150 including aproximal portion 111 having an end, a grafting portion 112, and a distalportion (not shown) having an end, the first top beam 150 configured forcontacting the first top-lateral surface 117 of the central beam and thefirst top-side surface 127 of the central beam 101 in the expanded state149 e, the central axis of the first top beam at least substantially on(i) a top plane containing the central axis of the first top beam andthe central axis of a second top beam and (ii) a first side planecontaining the central axis of the first top beam and the central axisof a first bottom beam. Likewise the frame 149 can be configured to havea second top beam 160 including a proximal portion 111 having an end, agrafting portion 112 having an end, and a distal portion (not shown)having an end, the second top beam 160 configured for contacting thesecond top-lateral surface 119 of the central beam 101 and the secondtop-side surface 132 of the central beam 101 in the expanded state 149e, the central axis of the second top beam at least substantially on (i)the top plane and (ii) a second side plane containing the central axisof the second top beam and the central axis of a second bottom beam.Likewise the frame 149 can be configured to have a first bottom beam 170including a proximal portion 111 having an end, a grafting portion 112,and a distal portion (not shown) having an end, the first bottom beam170 configured for contacting the first bottom-lateral surface 122 ofthe central beam 101 and the first bottom-side surface 129 of thecentral beam 101 in the expanded state 149 e, the central axis of thefirst bottom beam at least substantially on (i) a bottom planecontaining the central axis of the first bottom beam and the centralaxis of a second top beam and (ii) the first side plane. Likewise theframe 149 can be configured to have a second bottom beam 180 including aproximal portion 111 having an end, a grafting portion 112 having anend, and a distal region (not shown) having an end, the second bottombeam 160 configured for contacting the second bottom-lateral surface 124of the central beam 101 and the second bottom-side surface 134 of thecentral beam 101 in the expanded state 149 e, the central axis of thesecond bottom beam being at least substantially on (i) the bottom planeand (ii) a second side plane containing the central axis of the secondbottom beam and the second top beam.

In some embodiments, the central axis of the first top beam 150 can beat least substantially parallel to the central beam axis 105. Likewisethe frame 149 can be configured to have a second top beam 160 includinga proximal portion 111 having an end, a grafting portion 112 having anend, and a distal portion (not shown) having an end, the second top beam160 configured for contacting the second top-lateral surface 119 of thecentral beam 101 and the second top-side surface 132 of the central beam101 in the expanded state 149 e, the central axis of the second top beam160 being at least substantially parallel to the central beam axis 105.Likewise the frame 149 can be configured to have a first bottom beam 170including a proximal portion 111 having an end, a grafting portion 112,and a distal portion (not shown) having an end, the first bottom beam170 configured for contacting the first bottom-lateral surface 122 ofthe central beam 101 and the first bottom-side surface 129 of thecentral beam 101 in the expanded state 149 e, the central axis of thefirst bottom beam 170 being at least substantially parallel to thecentral beam axis 105. Likewise the frame 149 can be configured to havea second bottom beam 180 including a proximal portion 111 having an end,a grafting portion 112 having an end, and a distal region (not shown)having an end, the second bottom beam 160 configured for contacting thesecond bottom-lateral surface 124 of the central beam 101 and the secondbottom-side surface 134 of the central beam 101 in the expanded state149 e, the central axis of the second bottom beam 180 being at leastsubstantially parallel to the central beam axis 105.

As shown in FIG. 1D, the graft distribution systems provided herein havethe layered effect from the frame on the central beam that provides anadditive dimension, both laterally and vertically. The added dimensionallows for a low profile entry of the system into the intervertebraldisc space, a wide lateral profile after expansion in vivo to avoidbackout, as well as a sleeve for safe insertion of the central beambetween the top endplate and bottom endplate in the intervertebralspace. In some embodiments, the first top beam, second top beam, firstbottom beam, and second bottom beam can each have a transversecross-sectional wall thickness adding to the respective central beamdimension, the thickness ranging from about 0.5 mm to about 5.0 mm, fromabout 0.75 mm to about 4.75 mm, from about 1.0 mm to about 4.5 mm, fromabout 1.25 mm to about 4.25 mm, from about 1.5 mm to about 4.0 mm, fromabout 1.75 mm to about 3.75 mm, from about 2.0 mm to about 3.5 mm, fromabout 2.25 mm to about 3.25 mm, or any range therein in increments of0.05 mm. In some embodiments, the first top beam, second top beam, firstbottom beam, and second bottom beam can each have a transversecross-sectional wall thickness adding to the respective central beamdimension, the thickness ranging from about 1.5 mm to about 2.5 mm,including 1.5, 1.75, 2.0, 2.25, 2.5, or an amount therein in incrementsof 0.05 mm.

The beams of the laterovertically-expanding frame 149 can be operablyconnected through connector elements. As such, the frame 149 can includea plurality of proximal top connector elements 191 configured toexpandably connect the proximal portion 111 of the first top beam 150 tothe proximal portion 111 of the second top beam 160, the expandingconsisting of a flexing at least substantially on a top plane containingthe central axis of the first top beam 150 and the central axis of thesecond top beam 160. Likewise the frame 149 can be configured to have aplurality of distal top connector elements (not shown) configured toexpandably connect the distal portion of the first top beam 150 to thedistal portion of the second top beam 160, the expanding consisting of aflexing at least substantially on the top plane.

Likewise the frame 149 can be configured to have a plurality of proximalbottom connector elements 193 configured to expandably connect theproximal portion 111 of the first bottom beam 170 to the proximalportion 111 of the second bottom beam 180, the expanding consisting of aflexing at least substantially on a bottom plane containing the centralaxis of the first bottom beam 170 and the central axis of the secondbottom beam 180. Likewise the frame 149 can be configured to have aplurality of distal bottom connector elements (not shown) configured toexpandably connect the distal portion of the first bottom beam 170 tothe distal portion of the second bottom beam 180, the expandingconsisting of a flexing at least substantially on the bottom plane.

Likewise the frame 149 can be configured to have a plurality of proximalfirst side connector elements 195 configured to expandably connect theproximal portion 111 of the first top beam 150 to the proximal portion111 of the first bottom beam 170, the expanding consisting of a flexingat least substantially on a first side plane containing the central axisof the first top beam 150 and the central axis of the first bottom beam170; a plurality of distal first side connector elements (not shown)configured to expandably connect the distal portion of the first topbeam 150 to the distal portion of the first bottom beam 170, theexpanding consisting of a flexing at least substantially on the firstside plane. Likewise the frame 149 can be configured to have a pluralityof proximal second side connector elements 197 configured to expandablyconnect the proximal portion 111 of the second top beam 160 to theproximal portion 111 of the second bottom beam 170, the expandingconsisting of a flexing at least substantially on a second side planecontaining the central axis of the second top beam 160 and the centralaxis of the second bottom beam 180; a plurality of distal second sideconnector elements (not shown) configured to expandably connect thedistal portion of the second top beam 160 to the distal portion of thesecond bottom beam 180, the expanding consisting of a flexing at leastsubstantially on the second side plane.

In some embodiments, each plurality of proximal connector elements canbe configured as proximal struts in an at least substantially parallelalignment in the expanded state and the collapsed state; and, eachplurality distal connector elements are distal struts can be configuredin an at least substantially parallel alignment in the expanded stateand the collapsed state. As such, the proximal top struts can beconfigured monolithically integral to the first top beam and the secondtop beam and adapted to flex toward the distal top struts duringcollapse; and, the distal top struts can be configured monolithicallyintegral to the first top beam and the second top beam and adapted toflex toward the proximal top struts during collapse. Likewise, theproximal bottom struts can be configured monolithically integral to thefirst bottom beam and the second bottom beam and adapted to flex towardthe distal bottom struts during collapse; and, the distal bottom strutscan be configured monolithically integral to the first bottom beam andthe second bottom beam and adapted to flex toward the proximal bottomstruts during collapse. Likewise, the proximal first side struts can beconfigured monolithically integral to the first top beam and the firstbottom beam and adapted to flex toward the distal first side strutsduring collapse; and, the distal first side struts can be configuredmonolithically integral to the first top beam and the first bottom beamand adapted to flex toward the proximal first side struts duringcollapse. Likewise, the proximal second side struts can be configuredmonolithically integral to the second top beam and the second bottombeam and adapted to flex toward the distal second side struts duringcollapse; and, the distal second side struts can be configuredmonolithically integral to the second top beam and the second bottombeam and adapted to flex toward the proximal second side struts duringcollapse.

As shown in FIG. 1D, the frame 149 can be configured for slidablyengaging with the central beam 101 in vivo following placement of thecentral beam 101 in the intervertebral space through the annularopening, the slidably engaging including translating the central beam101 into the frame 149 from the proximal end 11 of the frame 149 towardthe distal end of the frame 149 in vivo; the translating includingkeeping the central beam axis 105 at least substantially coincident withthe central frame axis 113 during the translating to create the graftdistribution system 100 in vivo through the annular opening. The graftdistribution system 100 can also be configured to form a top graft-slabdepth 199 t between the top surface 115 of the central beam 101 and thetop vertebral endplate; and, a bottom graft-slab depth 199 b (not shown)between the bottom surface 120 of the central beam 101 and the bottomvertebral endplate in vivo. And, in some embodiments, the transversecross-section 110 of the graft distribution system 100 in vivo isgreater than the maximum lateral dimension of the annular opening toavoid backout.

One of skill will appreciate that the central beam can have anyconfiguration that would be operable with the teachings provided herein.In some embodiments, criteria for a suitable central beam may include acombination of a material and configuration that provides a suitablestiffness. In some embodiments, the central beam can comprise an I-beam.An example of an I-beam configuration and a complementarylaterovertically expandable cage are shown in FIGS. 1E and 1F.

One of skill will further appreciate that the central beam can have anyone or any combination of graft port configurations that would beoperable with the teachings provided herein. In some embodiments,criteria for a suitable graft port configuration may include acombination of port size, number of ports, and placement of ports. Insome embodiments, the central beam can comprise a side graft port.

One of skill will further appreciate that the connector elements canvary in design but should meet the constraints as taught herein. In someembodiments, for example each of the connector elements 191,193,195,197can have a cross-sectional aspect ratio of longitudinal thickness totransverse thickness ranging from 1:2 to 1:8. A section of a connectorelement is shown in FIG. 1G.

As such, the systems can also include an improved, low-profile,intervertebral disc cage that expands bidirectionally. Consistent withthe teachings herein, the cages offer several improvements to the artthat include, for example, preventing the cage from backing out of theannulus fibrosis after expansion in an intervertebral disc space. Assuch, the terms “cage,” “scaffold” and “scaffolding”, for example, canbe used interchangeably with “laterovertically expandable frame”,“expandable frame”, or “frame”, in some embodiments. The cages have theability to at least (i) laterally expand within the intervertebral spaceto avoid backout of the device through the annulotomy, (ii) verticallyexpand for distraction of the intervertebral space, (iii) provideadditional space within the device in the annulus for the introductionof graft materials; (iv) maintain a large, footprint to distribute loadover a larger area against the endplate, for example, by not contractingin length to expand in height and/or width; and, (v) insert into theannulus in a minimally-invasive manner using only a unilateral approach.

FIGS. 2A-2F illustrate a method of using a bidirectionally-expandablecage, according to some embodiments. As shown in FIGS. 2A-2B, an annulus205 is prepared with an annulotomy serving as a single point of entry210 and an intervertebral space 215 for insertion of a bidirectionallyexpandable cage system 250. As shown in FIGS. 2C-2F, the system 250 hasa cage 255 having a proximal end 256, a distal end 257, and a lumen 258that communicates with the intervertebral space 215 through anexpandable/collapsible bone graft window 259; a shim core 260 having atapered nose 262 at the distal end of the shim core 260; a releasablyattachable rail beam 265; a pusher 270 that slidably translates over theshim core 260 and the rail beam 265; a trial shim 275 having a shoulder277 and slidably translating over the rail beam 265 and shim core 260into the lumen 258 of the cage 255, and a permanent shim 280 having ashoulder 282 and slidably translating over the rail beam 265 and shimcore 260 into the lumen 258 of the cage 255.

The procedure for implanting the cage 255 begins in FIG. 2A, includinginserting a cannula (not shown) with a bullet-nosed obturator throughthe single point of entry 210 and inside the intervertebral disc space215 until contacting the opposing wall of the annulus 205. The cannula(not shown) depth is used to select the desired length of the cage 255.The shim core 260 is loaded with bone graft material and the rail beam265 is releasably attached to the shim core 260. The cage 255 is loadedonto the rail beam 265 and pushed onto the shim core 260 and into thecannula (not shown) using the pusher 270 until the distal end 257 of thecage 255 contacts the back of the tapered nose 262 of the shim core 260as shown in FIG. 2A. The assembly of the shim core 260 and the cage 255are inserted into the intervertebral space 215, and the cannula (notshown) is removed as shown in FIG. 2B. The lumen 258 of the cage 255 isloaded with bone graft material, and the trial shim 275 is slidablytranslated over the rail beam 265 and the shim core 260 into the lumen258 of the cage 255 as shown in FIG. 2C. A variety of sizes of the trialshim 275 can be tested until the largest trial shim 275 that will fit isfound, or until the trial shim having the desired vertical and lateraldimensions for expansion is used, in order to laterovertically expandthe cage 255 as desired. The trial shim 275 is then removed, and thelumen 258 of the cage 255 is again filled with bone graft material withthe shim core 260 remaining in place as shown in FIG. 2D. The permanentshim 280 is then slidably translated along the rail beam 265 and theshim core 260 into the intervertebral space 215 using the pusher 270until the distal end 257 of the cage 255 contacts the back of thetapered nose 262 of the shim core 260 to maintain the desiredlaterovertical expansion of the cage 255 as shown in FIG. 2E. The railbeam 265 is then disconnected from the shim core 260 as shown in FIG.2F.

It should be appreciated that the annulotomy can have nearly anydimension considered desirable to one of skill in the art. Theannulotomy can have a vertical dimension, for example, that is thedistance between a top vertebral plate and a bottom vertebral plate, thetop vertebral plate and the bottom vertebral plate defining the upperand lower borders of the intervertebral disc space. In some embodiments,the vertical dimension can range from about 4 mm to about 12 mm, about 5mm to about 11 mm, about 6 mm to about 10 mm, and about 7 mm to about 9mm, about 6 mm to about 8 mm, about 6 mm, or any range or amount thereinin increments of 1 mm. In some embodiments, the lateral dimension of thesingle point of entry can range from about 5 mm to about 15 mm, about 6mm to about 14 mm, about 7 mm to about 13 mm, about 8 mm to about 12 mm,about 10 mm, or any range or amount therein in increments of 1 mm. Insome embodiments, the single point of entry has an area with a diameterranging from about 2 mm to about 20 mm, from about 3 mm to about 18 mm,from about 4 mm to about 16 mm, from about 5 mm to about 14 mm, fromabout 6 mm to about 12 mm, from about 7 mm to about 10 mm, or any rangetherein. In some embodiments, the low profile has an area with adiameter of 2 mm, 4 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, 18 mm,or any range therein, including any increment of 1 mm in any suchdiameter or range therein. The low profile dimensions of the cagestaught herein are designed to fit within these dimensions.

One of skill will also appreciate that there are several methods anddevices that could be used to expand the cage. In some embodiments, theexpanding includes using a means for (i) laterovertically expanding thecage and (ii) creating a convex surface that at least substantiallycomplements the concavity of a surface of a vertebral endplate thatcontacts the pair of top beams or the pair of bottom beams.

One of skill will also appreciate a method that distracts theintervertebral space and laterally expands the cage to avoid back-out.As such, in some embodiments, the expanding includes introducing alaterovertical expansion member into the intervertebral space throughthe single point of entry and into the cage, the lateroverticalexpansion member configured to provide a vertical force through the cageand into the top vertical endplate and bottom vertical endplate todistract the intervertebral space; and, a lateral force on the firstside wall and the second side wall to expand the cage to a width that isgreater than the lateral dimension of the single point of entry toprevent the bidirectionally-expandable cage from backing out of theannulus fibrosis after the expanding.

One of skill will also appreciate having a method for passing bonegrafting material into the intervertebral space. As such, thelaterovertical expansion member can include a port for introducing thegrafting material into the intervertebral space. The methods and systemsprovided herein include the use of bone graft materials known to one ofskill. Materials which may be placed or injected into the intervertebralspace include solid or semi-solid grafting materials, bone from removedfrom patient's facet, an iliac crest harvest from the patient, and bonegraft extenders such as hydroxyapatite, demineralized bone matrix, andbone morphogenic protein. Examples of solid or semi-solid graftingmaterial components include solid fibrous collagen or other suitablehard hydrophilic biocompatible material. Some materials may also includeswelling for further vertical expansion of the intervertebral discspace.

One of skill will also appreciate having a method for retaining thelaterovertical expansion member in the cage. As such, the introducingcan include engaging a ratchet mechanism comprising a protuberance onthe laterovertical expansion member that engages with a strut of thecage to prevent the cage from backing out of the annulus fibrosis afterthe expanding. The ratchet mechanism can be, for example, similar to azip-tie ratchet mechanism having a gear component and a pawl component.In some embodiments, the cage has the gear component, for example,including the struts; and, the laterovertical expansion member is a shimdevice having the pawl component, for example, a projection that canangle toward the proximal end of the expansion member or away from thedirection of insertion of the shim device. In some embodiments, the cagehas the pawl component, for example, including the struts; and, thelaterovertical expansion member is a shim device having the gearcomponent, for example, a series of projections. In some embodiments, aprojection can angle from about 5° to about 75° toward the proximal endof the expansion member or away from the direction of insertion of theshim device.

One of skill will also appreciate having a method of designing the shapeof the cage upon expansion. As such, in some embodiments, the expandingincludes selecting a shim configured to create a convex surface on thetop surface of the top wall to at least substantially complement theconcavity of the respective top vertebral plate, and/or the bottomsurface of the bottom wall to at least substantially complement theconcavity of the respective bottom vertebral plate. In some embodiments,the expanding includes selecting a shim configured to vertically expandthe distal end of the cage more than the proximal end of the cage. And,in some embodiments, the expanding includes selecting a shim configuredto laterally expand the distal end of the cage more than the proximalend of the cage.

FIGS. 3A-3D illustrate collapsed and expanded views of abidirectionally-expandable cage for fusing an intervertebral disc space,according to some embodiments. FIGS. 3A and 3C show an expandedconfiguration, and FIGS. 3B and 3D show a collapsed configuration. Thecage 300 can comprise at least 4 walls 302, 304, 306, 308 that form acylinder having a long axis 309, the at least 4 walls 302, 304, 306, 308including a top wall 302 forming a top plane and having a top surfacewith protuberances (not shown) adapted to contact the top vertebralplate (not shown); a bottom wall 304 forming a bottom plane and having abottom surface with protuberances (not shown) adapted to contact thebottom vertebral plate (not shown); a first side wall 306 forming afirst side wall plane; and, a second side wall 308 forming a second sidewall plane. In these embodiments, each of the walls 302, 304, 306, 308can have at least 2 longitudinal beams, such that a rectangular cylindercan have a total of 4 longitudinal beams 312, 314, 316, 318; and, aplurality of struts 333 that (i) stack in the collapsed state of thecage 300, as shown in FIGS. 3B and 3D, to minimize void space in theirrespective wall for a low profile entry of the cage 300 both verticallyand laterally into a single point of entry (not shown) into anintervertebral disc space (not shown) and (ii) deflect upon expansion toseparate the at least 2 longitudinal beams of the total of 4longitudinal beams 312, 314, 316, 318 in the rectangular cylinder intheir respective wall 302, 304, 306, 308. In addition, the cage 300 canbe configured to expand laterally in the intervertebral space (notshown) to a size greater than a lateral dimension of the single point ofentry (not shown to prevent the bidirectionally-expandable cage 300 frombacking out of the annulus fibrosis (not shown) after the expandingshown in FIGS. 3A and 3C.

It should be appreciated that the collapsed configuration includes thedesign of a low profile entry through the annulus fibrosis to allow fora minimally-invasive procedure. In order to facilitate the use of aminimally-invasive procedure, the low profile entry of the collapsedconfiguration should be a substantially small area of entry having adiameter ranging, for example, from about 5 mm to about 12 mm for thesingle point of entry through the annulus fibrosis. In some embodiments,the low profile has an area with a diameter ranging from about 2 mm toabout 20 mm, from about 3 mm to about 18 mm, from about 4 mm to about 16mm, from about 5 mm to about 14 mm, from about 6 mm to about 12 mm, fromabout 7 mm to about 10 mm, or any range therein. In some embodiments,the low profile has an area with a diameter of 2 mm, 4 mm, 6 mm, 8 mm,10 mm, 12 mm, 14 mm, 16 mm, 18 mm, or any range therein, including anyincrement of 1 mm in any such diameter or range therein.

One of skill will appreciate that a variety of strut configurations maybe contemplated to minimize void space for the low profile entry of thecage into the intervertebral space. In some embodiments, each wall ofthe cage has a series of v-shaped struts 333 that (i) stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space in their respective wall for the low profile entryof the cage both vertically and laterally into the intervertebral space,and (ii) deflect upon expansion in a plane that is at leastsubstantially parallel to the plane of their respective wall to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312, 314, 316,318 in the rectangular cylinder in their respective wall and open a bonegraft window 366 to pass a bone graft material into the intervertebralspace in the expanded configuration. In some embodiments, the cage 300is configured to accommodate the lateral dimension of the single pointof entry ranging from about 5 mm to about 15 mm.

The v-shaped struts can be “V” shaped slots projected through each ofthe cage walls starting at a distance of 2 mm (0.5-4) from each cornerof the cage to effectively render the “V” shaped struts in the midregion of the wall faces, in which the struts can be fabricated ascontinuous with L shaped beams on the corners. The slots can be cut suchthat they are projected perpendicular to the faces or angled distallyfrom the outside of the cage to the inside of the cage. The distallyangled projection can facilitate insertion of the shims taught herein.And, the proximal faces of the corners of the beams can also haveinward, distally angled chamfers to facilitate insertion of the shimstaught herein. The struts can be uniform in thickness in theproximal-distal direction. In some embodiments, the struts range fromabout 0.2 mm to about 1.0 mm, from about 0.3 mm to about 0.9 mm, fromabout 0.4 mm to about 0.8 mm, from about 0.5 mm to about 0.7 mm inthickness, or any range therein in increments of about 0.1 mm. Thevertex of the “V” strut can trace along the center axis of the each ofthe side faces and can be radiused to dimension of 0.031″(0.005-0.062″), in some embodiments, to prevent stress cracking.Moreover, the shape of the strut or the slot projections can also be C,U, or W, in some embodiments. The struts can be 4 times thicker in thedirection perpendicular to the long axis of the cage than in thedirection of the long axis of the cage. In some embodiments, thisthickness ratio can range from about 2× to about 8×, from about 3× toabout 7×, from about 4× to about 6×, about 5×, or any range therein inincrements of 1×. This thickness can help maintain a high structuralstiffness and strength in the direction perpendicular to theproximal-distal axis so that the transverse cross section (perpendicularto the proximal-distal axis) shape is maintained during and afterinsertion of the cage into the intervertebral disc space.

In some embodiments, the angle of each strut can range from about140°-170° as measured at the vertex in the non-stressed state. In theseembodiments, the angle facilitates flexion of the legs of each struttowards each other upon moderate inward pressure to collapse the cagefor insertion into the disc space. Furthermore the angled strut lies ina plane at least substantially parallel to the plane of it's respectivewall, and in some embodiments to the long axis of the cage, so that theflexion does not alter the side wall thickness. This helps to maintainthe low profile for insertion while maximizing the lumen size. Thisgeometry combined with the solid beams on the corners helps ensure thatthe implant has a minimal change in length, less than 15% reduction inlength as measured along the long axis, when expanded more than 20%vertically and/or horizontally. As such, the top and bottom of the cagethat support the vertebra remain at least substantially constant inlength regardless of expansion.

In some embodiments, the cage 300 has v-shaped struts 333 and a bonegraft window 366 that (i) complements the v-shaped struts 333 in thecollapsed configuration and (ii) opens upon expansion to pass a bonegraft material into the intervertebral space in the open-complementaryconfiguration 355, which can also be referred to as an expandedconfiguration. And, in some embodiments, the cage 300 has a proximalregion 311, a proximal end 322, a distal region 388, a distal end 399,and at least one of the at least 4 walls 302, 304, 306, 308 having afirst series of v-shaped struts 333 that are configured to stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space for the low profile entry of the cage 300 into theintervertebral space; and, deflect upon expansion to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312, 314, 316,318 in the rectangular cylinder in their respective wall and open a bonegraft window 366 adapted to pass a bone graft material into theintervertebral space in the expanded configuration; wherein, the firstseries of v-shaped struts 333F is located in the proximal region of thecage, the vertices of the first series of v-shaped struts 333F pointingaway from the proximal end 322 of the cage 300 and toward the distal end399 of the cage 300. In some embodiments, the cage 300 can furthercomprise a second series of v-shaped struts 333S that stack in aclosed-complementary configuration 344 in the collapsed state tominimize void space for the low profile entry of the cage 300 into theintervertebral space; and, deflect upon expansion to anopen-complementary configuration 355 to separate the at least 2longitudinal beams of the total of 4 longitudinal beams 312, 314, 316,318 in the rectangular cylinder in their respective wall and open a bonegraft window 366 adapted to pass a bone graft material into theintervertebral space in the expanded configuration; wherein, the secondseries of v-shaped struts 333S is located in the distal region 388 ofthe cage 300, the vertices of the second series of v-shaped struts 333Spointing away from the distal end 399 of the cage 300 and toward theproximal end 322 of the cage 300. In such embodiments, the strutconfiguration can result in the expansion of the first series ofv-shaped struts 333F and the second series of v-shaped struts 333Screating a bone graft window 366 that opens to the bow-tie configurationshown in FIGS. 3A and 3C.

One of skill will also appreciate that the cage design providesflexibility in the relative amounts of lateral expansion and verticalexpansion, as well as the relative amounts of expansion proximally anddistally across the cage in either the lateral or vertical expansions.As such, in some embodiments, the cage is configured such that the ratioof the amount of lateral expansion to the amount of vertical expansionis variable. And, in some embodiments, the cage is configured such thatthe ratio of the amount of proximal expansion to the amount of distalexpansion is variable for lateral expansion or vertical expansion.

FIGS. 4A and 4B illustrate collapsed and expanded views of abidirectionally-expandable cage having a bone graft window on each wallfor fusing an intervertebral disc space, according to some embodiments.FIG. 4A shows the cage 400 in the collapsed configuration for alow-profile entry 405 into to single point of entry into anintervertebral disc space, and FIG. 4B shows the cage 400 in theexpanded configuration to distract the intervertebral disc space andavoid back-out of the cage through the single point of entry after theexpansion. As shown, each wall contains a bone graft window 466 forpassing bone graft material into the intervertebral disc space.

FIGS. 5A-5D illustrate system for fusing an intervertebral disc space,according to some embodiments. As shown, the system 550 has a cage 555having an expandable/collapsible bone graft window 566; a shim core 560having a tapered nose 562 at the distal end of the shim core 560 and abone graft window 566; a releasably attachable rail beam 565; a pusher(not shown) that slidably translates over the shim core 560 and the railbeam 565; a trial shim 575 having a shoulder 577 and slidablytranslating over the rail beam 565 and shim core 560 into the cage 555,and a permanent shim 580 having a shoulder 582 and slidably translatingover the rail beam 565 and shim core 560 into the cage 555. The systemcan comprise a bidirectionally-expandable cage having at least 4 wallsthat form a cylinder having a long axis. The at least 4 walls caninclude, for example, a top wall forming a top plane and having a topsurface with protuberances adapted to contact the top vertebral plate; abottom wall forming a bottom plane and having a bottom surface withprotuberances adapted to contact the bottom vertebral plate; and, afirst side wall forming a first side wall plane, and a second side wallforming a second side wall plane. Each of the walls can have at least 2longitudinal beams; and, a plurality of struts that (i) stack in thecollapsed state to minimize void space in their respective wall for alow profile entry of the cage both vertically and laterally into asingle point of entry into an intervertebral disc; and, (ii) deflectupon expansion to separate the at least 2 longitudinal beams in theirrespective wall. In some embodiments, the cage can be configured toexpand laterally in the intervertebral space to a size greater than alateral dimension of the single point of entry to prevent thebidirectionally-expandable cage from backing out of the annulus fibrosisafter the expanding. Moreover, the system can include a lateroverticalexpansion member configured to induce the laterally expanding and thevertically expanding of the cage; and, a core configured to guide thelaterovertical expansion member into the cage to induce the laterallyexpanding and the vertically expanding of the cage.

One of skill will appreciate that the laterovertical expansion membercan also be configured to slidably engage with the core totranslationally enter the cage in along the long axis of the cage. Insome embodiments, the lateral expansion can occur concurrent with thevertical expansion and, in some embodiments, the lateral expansion canoccur prior to the vertical expansion, for example, to reduce frictionalstress on the cage during the lateral expansion. A two stage shim, forexample, can be used. A first stage shim can be inserted to expand thecage laterally before inserting a second stage shim to expand the cagevertically. In some embodiments, the second stage shim can slidablytranslate along the first stage shim. The shim can be made of anymaterial considered desirable to one of skill, for example, a metal or apolymer. In some embodiments, the shim can comprise a non-resorbablepolymer material, an inorganic material, a metal, an alloy, or bone.

One of skill will appreciate that a system can include all or anycombination of the above. As such, the teachings also include system forfusing an intervertebral disc space, the system comprising abidirectionally-expandable cage having a proximal region, a proximalend, a distal region, a distal end, and at least 4 walls, the cagefabricated as a continuous single piece. In these embodiments, the atleast 4 walls form a cylinder having a long axis and include a top wallforming a top plane and having a top surface with protuberances adaptedto contact the top vertebral plate; a bottom wall forming a bottom planeand having a bottom surface with protuberances adapted to contact thebottom vertebral plate; and, a first side wall forming a first side wallplane, and a second side wall forming a second side wall plane. Each ofthe walls can have at least 2 longitudinal beams and a plurality ofstruts.

At least one of the walls can have a first series of v-shaped strutsthat are configured to stack in a closed-complementary configuration inthe collapsed state to minimize void space for a low profile entry ofthe cage through a single point of entry into an intervertebral discspace; and, deflect upon expansion to an open-complementaryconfiguration to separate the at least 2 longitudinal beams in theirrespective wall and open a bone graft window adapted to pass a bonegraft material into the intervertebral space in the expandedconfiguration. The first series of v-shaped struts can be located in theproximal region of the cage, the vertices of the first series ofv-shaped struts pointing away from the proximal end of the cage andtoward the distal end of the cage; and, the cage can be configured toexpand laterally in the intervertebral space to a size greater than alateral dimension of the single point of entry to prevent thebidirectionally-expandable cage from backing out of the annulus fibrosisafter the expanding. A laterovertical expansion member can be configuredto induce the laterally expanding and the vertically expanding of thecage; and, a core can be configured to guide the lateroverticalexpansion member into the proximal end of the cage, and along the longaxis of the cage, to expand the cage laterally and vertically. Moreover,the laterovertical expansion member can slidably engage with the core totranslationally enter the cage along the long axis of the cage.

One of skill will appreciate that the systems and system components canbe manufactured using any method known to one of skill in themanufacture of such intricate metal and/or polymeric components. Forexample, the cage can be fabricated in a partially expanded state or afully expanded state. Moreover, the cage can be manufactured to have nointernal stress or strain in the partially or fully expanded state whenno external loading is applied.

The system components can comprise any suitable material, or anycombination of materials, known to one of skill. For example, allcomponents can be metal, all components can be plastic, or thecomponents can be a combination of metal and plastic. One of skill willappreciate that the cages can have performance characteristics that arenear that of a bone structure, in some embodiments, such that thescaffoldings are not too stiff or hard, resulting in a localized loadingissue in which the scaffolding puts too much pressure on native bonetissue, and likewise such that the scaffoldings are too flexible orsoft, resulting in a localized loading issue in which the bone tissueputs too much pressure on the scaffolding. A radio-opaque material canbe employed to facilitate identifying the location and position of thescaffolding in the spinal disc space. Examples of such materials caninclude, but are not limited to, platinum, tungsten, iridium, gold, orbismuth.

One of skill can select materials on the basis of desired materialperformance characteristics. For example, one of skill will look toperformance characteristics that can include static compression loading,dynamic compression loading, static torsion loading, dynamic torsionloading, static shear testing, dynamic shear testing, expulsion testing,and subsidence testing. The parameters for upper and lower limits ofperformance for these characteristics can fall within the range ofexisting such spinal devices that bear the same or similar environmentalconditions during use. For example, a desired static compression loadingcan be approximately 5000N. A desired dynamic compression loading canhave an asymptotic load level of 3000N at 5×10⁶ cycles or 1500N at10×10⁶ cycles. The desired load level can range, for example, from about1.0× to about 2.0×, from about 1.25× to about 1.75×, or any rangetherein in increments of 0.1×, the vertebral body compression strength.Examples of standard procedures used to test such performancecharacteristics include ASTM F2077 and ASTM F2624.

Examples of suitable materials can include non-reinforced polymers,carbon-reinforced polymer composites, PEEK (polyether ketone) and PEEKcomposites, polyetherimide (ULTEM), polyimide, polyamide or carbonfiber. Other examples include metals and alloys comprising any one ormore components including, but not limited to, shape-memory alloys,nickel, titanium, titanium alloys, cobalt chrome alloys, stainlesssteel, ceramics and combinations thereof. In some embodiments, thecomponents are all titanium or titanium alloy; all PEEK; or acombination of titanium or titanium alloy and PEEK. In some embodiments,the cage comprises titanium or titanium alloy, and the shim comprisesPEEK. In some embodiments, the scaffolding can comprise a metal frameand cover made of PEEK or ULTEM. Examples of titanium alloys can includealloys of titanium, aluminum, and vanadium, such as Ti₆Al₄V in someembodiments.

In some embodiments, the cage can be fabricated from strong and ductilepolymers having a tensile modulus of about 400,000 psi or more, and atensile strength of about 14,000 psi or more. Such polymers may alsohave the ability to strain more than 4% to break, and perhaps at least20% to break in some embodiments. The materials can be stiffened bybeing filled with glass fibers or carbon fibers in some embodiments.

Bone ingrowth is desirable in many embodiments. As such, the scaffoldingcan comprise materials that contain holes or slots to allow for suchbone ingrowth. Consistently, the scaffoldings can be coated withhydroxyapatite, or other bone conducting surface, for example, bonemorphogenic protein, to facilitate bone ingrowth. Moreover, the surfacesof the scaffoldings can be formed as rough surfaces with protuberances,insets, or projections of any type known to one of skill, such as teethor pyramids, for example, to grip vertebral endplates, avoid migrationof the scaffolding, and encourage engagement with bone ingrowth.

The methods and systems provided herein include the use of bone graftmaterials known to one of skill. Materials which may be placed orinjected into the intevertebral space include solid or semi-solidgrafting materials, bone from removed from patient's facet, an iliaccrest harvest from the patient, and bone graft extenders such ashydroxyapatite, demineralized bone matrix, and bone morphogenic protein.Examples of solid or semi-solid grafting material components includesolid fibrous collagen or other suitable hard hydrophilic biocompatiblematerial. Some materials may also include swelling for further verticalexpansion of the intervertebral disc space.

The systems taught herein can be provided to the art in the form ofkits. A kit can contain, for example, a cage, a vertical expansionmember, and a bone graft material. In some embodiments, the kit willcontain an instruction for use. The vertical expansion member can be anyvertical expansion mechanism or means taught herein. For example, thevertical expansion member can be a shim. In some embodiments, the kitincludes a graft-injection shim for temporarily distracting theintervertebral space, the graft-injection shim having a port forreceiving and distributing the bone graft material in the intervertebralspace. In these embodiments, the graft-injection shim can remain as apermanent shim or be removed and replaced with a permanent shim.

FIG. 6 is a flowchart of a method of using a bidirectionally-expandablecage, according to some embodiments. The methods can include creating605 a single point of entry into an intervertebral disc, theintervertebral disc having a nucleus pulposus surrounded by an annulusfibrosis, and the single point of entry having a lateral dimensioncreated through the annulus fibrosis. The methods can also includeremoving 615 the nucleus pulposus from within the intervertebral throughthe single point of entry, leaving an intervertebral space for expansionof a bidirectionally-expandable cage within the annulus fibrosis, theintervertebral space having a top vertebral plate and a bottom vertebralplate. The methods can also include inserting 625 abidirectionally-expandable cage through the single point of entry intothe intervertebral space. Moreover, the methods can include expanding635 the cage in the intervertebral space both laterally and vertically,adding 645 a grafting material to the intervertebral space through thesingle point of entry, and inserting 665 a permanent shim into the cage.

One of skill will appreciate having the ability to control the amountsof vertical expansion and lateral expansion of the cage to accommodate avariety of applications, for example, to accommodate a varietyannulotomy dimensions used for the single point of entry. As such, insome embodiments, the expanding 635 includes selecting 655 an amount oflateral expansion independent of an amount of vertical expansion. Thelateral expanding of the cage can be selected, for example, to exceedthe lateral dimension of the single point of entry through an annulotomyby a desired amount to avoid, or prevent, the cage from backing out ofthe intervertebral space after expansion.

As such, methods of fusing an intervertebral space are provided hereinusing any of the graft distribution systems taught herein. The methodscan include creating a single point of entry into an intervertebraldisc, the intervertebral disc having a nucleus pulposus surrounded by anannulus fibrosis, and the single point of entry having the maximumlateral dimension created through the annulus fibrosis. The methods canalso include removing the nucleus pulposus from within theintervertebral disc through the single point of entry, leaving theintervertebral space for expansion of the graft distribution systemwithin the annulus fibrosis, the intervertebral space having the topvertebral plate and the bottom vertebral plate. The methods can alsoinclude inserting the laterovertically expanding frame in the collapsedstate through the single point of entry into the intervertebral space;and, inserting the central beam into the frame to form the graftdistribution system. Moreover, the methods can also include adding agrafting material to the intervertebral space through the entry port.

FIGS. 7A-7F illustrate some additional features of graft distributionsystems, according to some embodiments. The graft distribution systems700 provided herein have at least a top exit port 740 and a bottom exitport 741 in the grafting portion of the central beam 701, but they canalso contain side ports 742,743, such that there at least 4 graftdistribution ports in some embodiments. In some embodiments, the centralbeam 701 further comprises a first side graft port 742 and a second sidegraft port 743, in addition to a locking clip 702 at the proximal end ofthe central beam. In some embodiments, the laterovertically-expandingframe 749 can be a monolithically integral frame, optionally having a“bullet nose” 703 at the distal end of the frame for safe position ofthe cage against the anterior inner annulus in vivo, and adapted to opena graft distribution window 788 on at least the top and bottom sides, aswell as the first side and second side in some embodiments containingside ports, upon expansion of the connector elements to facilitate graftdistribution within the intervertebral space.

The distal end of the frame 749 can be configured to have alaterovertically operable connection with a guide plate 707 thatrestricts the first top beam, the first bottom beam, the second topbeam, and the second bottom beam to laterovertical movement relative tothe guide plate when converting the frame from the collapsed state tothe expanded state in vivo. And, in some embodiments, thelaterovertically-expandable frame has a lumen, and the guide plate has aluminal side with a connector 708 for reversibly receiving a guide wirefor inserting the laterovertically-expandable frame into theintervertebral space. In some embodiments, the frame has a chamferinside the proximal end of the frame beams to facilitate insertion ofcentral beam. And, in many embodiments, the frames have means forcreating friction between the vertebral endplates and the frame, such asprotuberances, for example cleat-type structures 704, to further avoidbackout.

As can be seen in at least FIG. 7, the bone graft distribution systemsprovided herein include bone graft windows defined by the connectorelements, the bone graft windows opening upon expansion of thelaterovertically expanding frame. In some embodiments, the methodfurther comprises opening a bone graft window, wherein the connectorelements include v-shaped struts that (i) stack either proximally ordistally in a closed-complementary configuration in the collapsed stateto minimize void space for a low profile entry of the system bothvertically and laterally into the intervertebral space, and (ii) deflectupon expansion to open the bone graft window.

It should be appreciated that the bone graft distribution systemsprovided herein also allow for independent expansion laterally andvertically by expanding in steps. In some embodiments, the expandingincludes selecting an amount of lateral expansion independent of anamount of vertical expansion. And, in some embodiments, the lateralexpansion exceeds the width of the annular opening that is the singlepoint of entry into the intervertebral space. For example, the lateraldimension of the single point of entry can range from about 5 mm toabout 15 mm in some embodiments. As such, in some embodiments, theexpanding includes expanding the laterovertically expanding framelaterally to a width that exceeds the width of the single point ofentry; and, inserting the central beam to expand the lateroverticallyexpanding frame vertically to create the graft distribution system.

The bone graft distribution systems provided herein also have additionalmeans for retaining the central beam in the laterovertically expandingframe. In some embodiments, the inserting of the central beam into thelaterovertically expanding frame includes engaging a ratchet mechanismcomprising a protuberance on the central beam that engages with thelaterovertically-expanding frame to prevent the central beam frombacking out of the laterovertically-expanding frame after the expanding.

Moreover, the bone graft distribution systems provided herein can be inthe form of a kit. The kits can include, for example, a graftdistribution system taught herein, a cannula for inserting the graftdistribution system into the intervertebral space, a guidewire adaptedfor guiding the central beam into the laterovertically expanding frame,and an expansion handle for inserting the central beam into thelaterovertically expanding frame to form the graft distribution system.

FIGS. 8A-8D illustrate components of a graft distribution kit, accordingto some embodiments. FIGS. 8A and 8B illustrate a 4-sided funnel cannula805 as taught herein having a shaft 810 forming a channel 815, a funnel820 for guiding a laterovertically expandable frame into an annulus in alow-profile configuration, the cannula shown with an obturator 825 inthe channel 815 of the cannula 805, the cannula 805 insertedposterolaterally through an annulotomy 877 in the annulus 888, into anintervertebral space 899, with the distal end of the cannula 805position near the inner anterior wall of the annulus 888. FIG. 8Cillustrates FIG. 8A with a guidewire used to insert the lateroverticallyexpandable frame 749 into the funnel 820 of the cannula 805 to guide theframe 749 into the annulus 888 in the low profile, collapsed state ofthe frame 749. FIG. 8D illustrates an expansion handle 855 havingtrigger 856 that pushes a pushrod 857 along the guidewire 866 whileholding the guidewire to push on the proximal end of the central beam701 to insert the central beam 701 into the frame 749 to expand theframe 749 by applying equal, or substantially equal forces: aproximally-directed force, Fp, at the connection 708 between the guideplate 707 and the guide wire 866 onto the distal portion of the beams ofthe frame 749, and a distally-directed force, FD, at the proximal end ofthe central beam 701.

FIGS. 9A-9C illustrate the expansion of a laterovertically-expandableframe in an intervertebral space, according to some embodiments. FIG. 9Ashows a collapsed frame 949 receiving a central beam 901 along aguidewire 966. FIG. 9B shows the central beam 901 partially insertedinto the frame 949 in an expanded state, the guidewire 966 still inplace FIG. 9C shows how the expanded state may appear when insertedposterolaterally and expanded in the intervertebral space in an annulus988. Side ports 942, 943 for bone graft distribution are shown throughan open bone graft window in the expanded frame 749.

FIGS. 10A-10C illustrate profiles of an expanded graft distributionsystem to highlight the exit ports and bone graft windows, according tosome embodiments. Profiles of an expanded frame 1049, highlighting bonegraft windows 1088 and graft ports 1040, 1041, 1042, 1043 as they mayappear in an intervertebral space after an implant procedure. Theguidewire 1066 is shown as remaining in place.

FIGS. 11A and 11B compare an illustration of the graft distribution inplace to a test placement in a cadaver to show relative size, accordingto some embodiments. Likewise, FIGS. 12A-12C show x-rays of a placementin a cadaver, according to some embodiments.

As described above, the frame 149 can be configured such that thecentral axis of the first top beam 150 is at least substantially on (i)the top plane and (ii) the first side plane; the central axis of thesecond top beam 160 is at least substantially on (i) the top plane and(ii) the second side plane; the central axis of the first bottom beam170 is at least substantially on (i) the bottom plane and (ii) the firstside plane; and, the central axis of the second bottom beam being atleast substantially on (i) the bottom plane and (ii) the second sideplane. It should be appreciated that this configuration provides a “topface” framed by the first top beam and the second top beam, a “bottomface” framed by the first bottom beam and the second bottom beam, a“first side face” framed by the first top beam and the first bottombeam, and a “second side face” framed by the second top beam and thesecond bottom beam.

In some embodiments, it can be desirable to have the frame expand toshape that is predesigned to fit between the top endplate and the bottomendplate of the intervertebral space in a manner that calls, forexample, for opposing faces of the frames to be something other than “atleast substantially parallel.” For example, it may be desired to havethe two opposing sides of the frame expand such that the central axis ofthe first top beam is no longer at least substantially parallel to thecentral axis of the second top beam. Likewise, it may be desired to havethe two opposing sides of the frame expand such that the central axis ofthe first bottom beam is no longer at least substantially parallel tothe central axis of the second bottom beam. Likewise, it may be desiredto have the opposing top and bottom sides of the frame expand such thatthe central axis of the first top beam is no longer at leastsubstantially parallel to the central axis of the first bottom beam.Likewise, it may be desired to have the opposing top and bottom sides ofthe frame expand such that the central axis of the second top beam is nolonger at least substantially parallel to the central axis of the secondbottom beam. Or, any combination of the above may be desired. Thelaterovertically expandable frames taught herein enable each of thesedesirable configurations.

FIGS. 13A-13D show orientations of the first top beam relative to thesecond top beam, first bottom beam relative to the second bottom beam,first top beam relative to the first bottom beam, and the second topbeam relative to the second bottom beam, according to some embodiments.FIG. 13A shows the first top beam 150 relative to the second top beam160, in which the angle ⊖_(T) is formed by the two beams to shape thetop face of the frame. FIG. 13B shows the first bottom beam 170 relativeto the second bottom beam 180, in which the angle ⊖_(B) is formed by thetwo beams to shape the bottom face of the frame. FIG. 13C shows thefirst top beam 150 relative to the first bottom beam 170, in which theangle ⊖_(FS) is formed by the two beams to shape the first side face ofthe frame. FIG. 13D shows the second top beam 160 relative to the secondbottom beam 180, in which the angle ⊖_(SS) is formed by the two beams toshape the second side face of the frame. In some embodiments, each of⊖_(T), ⊖_(B), ⊖_(FS), and ⊖_(SS) can be independently selected and eachcan range from 0° to 32°, from 0.5° to 31.5°, from 0.1° to 31.0°, from1.5° to 30.5°, from 2.0° to 30.0°, from 2.5° to 29.5°, from 3.0° to29.0°, from 3.5° to 28.5°, from 4.0° to 28.0°, from 4.5° to 27.5°, from5.0° to 27°, from 5.5° to 26.5°, from 6.0° to 26.0°, from 6.5° to 25.5°,from 7.0° to 25.0°, from 7.5° to 25.5°, from 8.0° to 26.0°, from 8.5° to26.5°, from 9.0° to 26.0°, from 9.5° to 25.5°, from 10.0° to 25.0°, from10.5° to 24.5°, from 11.0° to 24.0°, from 11.5° to 23.5°, from 12.0° to23.0°, from 12.5° to 22.5°, from 13.0° to 22.0°, from 13.5° to 21.5°,from 14.5° to 21.0°, from 15.5° to 20.5°, from 16.0° to 20.0°, from16.5° to 19.5°, from 17.0° to 19.0°, or any range therein in incrementsof 0.1°. In some embodiments, each of ⊖_(T), Θ_(B), ⊖_(FS), and ⊖_(SS)can be independently selected and each can be about 1°, 2°, 3°, 4°, 5°,6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°,21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°,35°, or any angle therein in increments of 0.1°.

It should be appreciated that the beams can each be independentlydesigned to have its own, independently selected curvature, whetherconvex or concave, and the curvatures can be the same or differentbetween beams that share a face of the frame. And, the curvatures can beopposing for beams that form opposing faces of the frame. Moreover, theframe can have a mixture of one or more straight and one or more curvedbeams.

Given the above, it should be appreciated that the frames can bedesigned according to nearly any opening bordered by the top vertebralendplate and bottom vertebral endplate of an intervertebral space, aswell as according to a given clinical treatment regardless of theopening dimensions prior to treatment. In some embodiments, the top faceof the frame can be at least substantially parallel to the bottom faceof the frame, whereas the first side face of the frame and the secondside face of the frame can be oriented at angles Θ_(T) and Θ_(B),wherein Θ_(T) and Θ_(B) can be independently selected to be the same ordifferent. Likewise, in some embodiments, the first side face of theframe can be at least substantially parallel to the second side face ofthe frame, whereas the top face of the frame and the bottom face of theframe can be oriented at angles Θ_(FS) and Θ_(SS), wherein Θ_(FS) andΘ_(SS) can be independently selected to be the same or different. Insome embodiments, each of Θ_(T), Θ_(B), Θ_(FS), and Θ_(SS) can beindependently selected to range from about 5° to about 32°, from about7° to about 22°, and from about 8° to about 16°, in some embodiments. Assuch, any of a variety of frames can be constructed from any of avariety of quadrilateral structures having the angles taught herein.

One of skill will appreciate that the teachings provided herein aredirected to basic concepts that can extend beyond any particularembodiment, embodiments, figure, or figures. It should be appreciatedthat any examples are for purposes of illustration and are not to beconstrued as otherwise limiting to the teachings. For example, it shouldbe appreciated that the devices provided herein can also be used asimplants in other areas of the body. The devices provided herein can beused, for example, in intravertebral body procedures to support ordistract intervertebral bodies in the repair of, for example, collapsed,damaged or unstable vertebral bodies suffering from disease or injury.

We claim:
 1. An intervertebral scaffolding system for use in a subject,comprising; a central beam having a proximal portion and a distalportion, wherein the central beam is sized to have a transversecross-section having a maximum dimension ranging from 5 mm to 15 mm forplacing the central beam into an intervertebral space through an annularopening having a maximum lateral dimension ranging from 5 mm to 15 mm;and, an expanding frame having a collapsed state and an expanded state,the frame configured for operably contacting the central beam to createan intervertebral scaffolding system in vivo, the frame having aproximal end and a distal end; and, a lumen formed by the expandingframe, the lumen of the frame configured for slidably engaging with thecentral beam in vivo following placement of the central beam in theintervertebral space through the annular opening, the slidably engagingincluding translating the central beam into the frame from the proximalend of the frame toward the distal end of the frame in vivo.
 2. Thescaffolding system of claim 1, wherein the scaffolding has a localizedloading range from about 1.0× to about 2.0× the vertebral bodycompression strength of the subject.
 3. The scaffolding system of claim1, wherein the scaffolding has a top surface that supports a topvertebral endplate, a bottom surface that supports a bottom vertebralendplate, and the top surface and the bottom surface remain at leastsubstantially constant in length regardless of the amount of expansion.4. The scaffolding system of claim 1, the central beam comprising anI-beam.
 5. The scaffolding system of claim 1, the central beam furthercomprising a grafting port.
 6. The scaffolding system of claim 1,wherein the scaffolding comprises a plurality of beams interconnected bya plurality of struts configured in an at least substantially parallelalignment in the collapsed state.
 7. The scaffolding system of claim 1,wherein the struts are configured monolithically integral to the topbeam and the bottom beam.
 8. A method of fusing an intervertebral spaceusing the scaffolding system of claim 1, the method comprising: creatinga point of entry into an intervertebral disc, the intervertebral dischaving a nucleus pulposus surrounded by an annulus fibrosis; removingthe nucleus pulposus from within the intervertebral disc through thepoint of entry, leaving the intervertebral space for expansion of thescaffolding system of claim 1 within the annulus fibrosis, theintervertebral space having a top vertebral plate and a bottom vertebralplate; inserting the expanding frame in the collapsed state through thepoint of entry into the intervertebral space; inserting the central beaminto the frame to form the scaffolding system; and, adding a graftingmaterial to the intervertebral space.
 9. The method of claim 8, whereinthe connector elements are struts are adapted to stack in the collapsedstate to minimize void space for a low profile entry of the frame intothe intervertebral space.
 10. The method of claim 8, wherein theexpanding includes expanding the expanding frame laterally to a widththat exceeds the width of the point of entry; and, inserting the centralbeam to expand the expanding frame vertically to support the frame inthe expanded state.
 11. A kit, comprising: the scaffolding system ofclaim 1; a cannula for inserting the scaffolding system into theintervertebral space; a guidewire adapted for guiding the central beaminto the expanding frame; and, an expansion handle for inserting thecentral beam into the expanding frame to form the scaffolding system.12. The kit of claim 11, the distal end of the frame having a slidablytranslational connection with a guide that restricts the expandableframe to movement relative to the guide when converting the frame fromthe collapsed state to the expanded state in vivo.
 13. The kit of claim11; wherein, the expandable frame has a plurality of beamsinterconnected by struts, and the struts are configured monolithicallyintegral to the plurality of beams.
 14. An intervertebral scaffoldingsystem, comprising: a plurality of beams that define an expandable framecomprising a collapsed state and an expanded state, the plurality ofbeams configured at least substantially parallel in the collapsed stateand define a proximal-distal axis, and a plurality of connector elementsthat operably connect the plurality of beams and maintain a highstructural stiffness and strength in the direction perpendicular to theproximal-distal axis so that a transverse cross section perpendicular tothe proximal-distal axis maintains shape during and after insertion ofthe frame into the intervertebral disc space, a lumen surrounded by theplurality of beams; a central beam configured for translatably insertinginto the lumen to expand the expandable frame.
 15. The scaffoldingsystem of claim 14, wherein the plurality of connector elements areconfigured monolithically integral to the plurality of beams.
 16. Thescaffolding system of claim 14, wherein, the connector elements arestruts configured monolithically integral to the plurality of beams. 17.The scaffolding system of claim 14, the distal end of the frame having aguide that restricts the movement of the plurality of beams whenconverting the frame from the collapsed state to the expanded state invivo.
 18. The scaffolding system of claim 14, the central beam furthercomprising a graft port.
 19. The scaffolding system of claim 14, whereinthe plurality of beams include a first top beam, a first bottom beam, asecond top beam, and a second bottom beam; wherein, the first top beamand the first bottom beam form an angle ⊖_(FS), the second top beam andthe second bottom beam form an angle ⊖_(SS), and each of ⊖_(FS)and⊖_(SS) are independently selected as something other than 0°, such that(i) the first top beam and the first bottom beam or (ii) the second topbeam and the second bottom beam, are not substantially parallel in theexpanded state; ⊖_(FS)and ⊖_(SS) are each independently selected torange from about 0.5° to 31.5°.
 20. The scaffolding system of claim 19,wherein ⊖_(FS) and ⊖_(SS) are each independently selected to be about1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°,17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°,31°, 32°, 33°, 34°, 35°, or any angle therein in increments of 0.1°.